SU1414593A1 - Self-adjusting system for controlling working cyclone of crossfeed in infeed grinding - Google Patents

Abstract

The invention relates to a machine tool industry and is intended for the automatic control of the size of the parts to be ground and the cross-feed working cycles on mortise grinding machines. The purpose of the invention is to improve the accuracy and performance, as well as stabilize the quality indicators of machining parts due to the properties of self-tuning to a change in the cutting ability of the grinding wheel and to a variation of the stiffness of the elastic system. The system contains sensor 1 allowance, adjusters 12,13 and 14 speeds, respectively, of finishing and roughing the quick slide of the carriage, adjusters 7 and 8 allowances for finishing and nursing, respectively, actuators 9, 10 and 11, respectively caliper retraction, gauge 20 gauge, null organs, two transducers 3 and 22. Two differentiating devices 17 and 23 were added to the system, a subtractive device 16, a computation unit 18, an inter measurement unit 19 time shafts and memory block 24. When processing the detail, signals from sensor 1 and sensor 20 for measuring the stroke of the grinding caliper are transmitted through converters 3 and 22 to a reading device 16, the output of which is a signal proportional to the radial component of the elastic deformation of the AIDS system. The current value of elastic deformation is used to determine the time constant, the automatic adjustment of the processing mode is made depending on the value of the time constant. 2 Il. (O ate with

Description

The invention relates to a machine tool and is designed to automatically control the size of the grinded parts and the working cycles of the cross feed on mortise grinding machines. The purpose of the invention is improving accuracy and productivity, as well as stabilizing the quality indicators of machining parts due to the properties of self-tuning to the change in the cutting ability of the grinding wheel and to the variation of the rigidity of the elastic system. The system contains a sensor 1 allowance, dials 12,13

and 14 speeds, respectively, of the finishing and roughing of the quick slide of the caliper, setting devices 7 and 8 allowances, respectively, for the finishing and nursing, actuators 9, 10 and 11, respectively, of the drive of the rough fee, the fine feed and the fast draining of the caliper, sensor 20 measuring the progress of the grinding caliper, null organs, two transducers 3 and 22. Two differentiating devices 17 and 23, a subtractive device 16, a computing unit 18, a time interval measuring unit 19 and a memory unit 24 are entered into the system. When processing the details, signals from the sensor 1 allowance and sensor 20 measuring the stroke of the grinding caliper are transmitted through converters 3 and 22 to a subtractor 16, the output of which produces a signal proportional to the radial component of the elastic deformation of the AIDS system. The current value of the elastic deformation is used to determine the time constant, the automatic adjustment of the processing mode is made depending on the value of the time constant. 2 Il.

SC "1414593

one

1414593

2

The invention relates to machine tools and is intended for automata. tactical management of the size of fume parts and the working cycles of the cross feed on mortise grinding machines.

The purpose of the invention is to improve the accuracy and performance, as well as stabilize the quality indicators of machining parts due to the properties of self-adjustment (adaptation) to changes in the cutting ability of the grinding wheel and variations in the rigidity of the elastic system.

FIG. 1 is a functional diagram of a self-adjusting system of control of the working cycle of the cross feed during mortise grinding; FIG. 2 - graphs of the variation of the cross feed rate \ 1 _С (3) and the removal rate ν _μ (5) as a function of the current allowance 9 for different values of the grinding time constant T _о ^, illustrating the principle. cip action system.

The system contains an allowance sensor 1 that controls the current allowance of the part 2 and is connected in series with the first converter 3, the output of which is connected to the first inputs of the first, second and third null organs 4, 5 and 6. The second inputs of the first 4 and second null organs are connected respectively, to setters 7 and 8 allowances for finishing and nursing. The outputs of the zero-bodies 4-6 are connected respectively to the first inputs of the actuators 9 and 10 of the actuator rough and fair feed and the actuator 11 quick slide caliper, the second inputs of which are connected to the outputs of the set points 12-14 speeds rough, fair feed and fast withdrawal speed caliper.

The outputs of the Executive elements 9-11 are connected respectively to the first, second and third inputs of the mechanism 15 drive cross feed. The second output of the first converter 3 is connected to the first input of the subtracting device 16, and the third output of this converter is connected to the input of the first differentiating device 17, the output of which is connected to the first inputs of blocks 18 and 19, respectively, computing and measuring time intervals, the second inputs of which are connected to the output of the first null organ

4. The output of the sensor 20 measuring the progress of the grinding caliper 21 through the first output of the second transducer 22 is connected to the second input of the subtractive device 16, the output of which is connected to the third input of the computing unit 18. The second output of the second transducer 22 through the second differentiating device 23 is connected to the fourth input of the computing unit 18. The output of the time interval measurement unit 19 is connected to the fifth input of the computing unit 18, the output of which is connected to the input of the memory unit 24, the first and second outputs of which are connected to the third inputs of the first 4 and second 5 null-organs, respectively.

FIG. 2 is presented in the form of a broken line 25-26-27-28-29-30-0 graph of the change in the cross feed rate ν _ο (5) as a function of the current allowance within one working cycle of processing a part. It contains a step of rough grinding (line 26-27) at a constant speed infeed U _{C |} , the stage of fine grinding at a constant transverse feed rate of U _sg (line 28-29) and the nursing stage (line 30-0) with a fixed transverse feed support. Switching from the first stage of ι to the second, and from the second to the stage of nursing is carried out at the current values of allowance δ, and δ ^ οοοτβββτγstuino, formed with the help of the first 4 and second 5 null organs. Corresponding to this working cycle V, (5) the curve of change in the metal removal rate ν _Μ as a function of the current allowance 5 with an acute grinding wheel and the time constant of the grinding process T _? y is represented by the curve 25-31-32-33-34-0. At the end of the working cycle, the final metal removal rate has a predetermined value ν'2 "at which the required surface roughness is ensured.

If the grinding wheel is blunted, its cutting ability deteriorates, the time constant T _о ^ increases and equals> T _о ^ ,. In this case, the curve of change in the metal removal rate ν _Μ (δ) is represented by the curve 25-35-32-36-37-0. Metal removal rate at the end of grinding is higher than the target

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roughness conditions ^ν "κ ' ^which can lead to defective parts on this quality indicator and, moreover, the removal rate of the metal in the area of final grinding may exceed the permissible values (section 37-38) and on this indicator The item may be out of order.

In order to avoid rejects and scatter on roughness in terms of changes in the time constant T _о ^ due to a change in the cutting ability of the wheel or the rigidity of the elastic system of the grinding machine, the operating cycle is automatically switched from the roughing feed to the finishing, from finishing to nursing.

In particular, for the situation in question, the deterioration of the cutting ability of a circle both of these allowances increase in proportion to the current value of T _in y and they respectively constitute (FIG. 2) the values 5 ₃ and 3 ₄ .

Thus, the graph of the change in the transverse feed rate as a result of self-tuning of the working cycle is presented as a broken line 25-26-39-40-41-42-0, and the corresponding graph of the change ν _Μ (5) in the form of the curve 25-35-43 -44-34-0. At the end of processing, the metal removal rate is equal to the specified value according to the roughness conditions.

I

The system works as follows.

When machining part 2, information about the removed allowance 5 (s) is converted into an electrical signal using the sensor 1 of the allowance and the first converter 3. At the same time, using the sensor 20 and the second converter 22, the movement of 5 _s (s) of the grinding slide 21 is also converted into an electrical signal. Electrical analogs of signals 5 (ί) and 5 _e (s) are fed to subtractive device 16, the output of which is a signal proportional to the radial component of the elastic deformation of the AIDS system

^{= 5c (s)} ” ^{8 (e) (1)}

The current value of elastic deformation (b) is used in the proposed device to determine pos η

time T _o y. It is possible

do based on solving a differential equation describing the grinding process

^{+ 5 (0 = 5s (g) (2)}

ten

15

20

Using equations (1) and (2), it is possible to determine the amount of elastic deformation at the first stage of machining a part at the speed of roughing feed ν ₀ , '

>< ³⁾

Based on (3), it is possible to calculate the time constant T _о ^ of the grinding process without resorting to the operation of differentiating the signal 5 (ϋ), namely

^τ ° ι ^1η V

ν _ε , T _about

(four)

25

Where

- the amount of elastic deformation at time

The accuracy of the determination is greatly affected by the error

3θ Forms parts that are large at the initial stage of processing. Therefore, in the proposed device, the value T _o ^ determined according to (4), is used only for the correction of the allowance

for fine grinding. More exactly35

The final determination of the time constant of the grinding process Т _О y is carried out at the stage of finishing grinding with the speed of transverse feeding V from

the equations

40

⁵ "> ^(C) ' ⁵ I · / ^{4 + ν} " ^Τ 0, <> - _

45 where "the amount of elastic deformation at a point in time.

Equation (5) allows you to determine the βθ time constant of the grinding process T _o ^ pa the second stage of processing

(6)

To reduce the amount of computation by expressions (4) and (6), the proposed device provides a procedure for replacing T _o ^ with the current time V and solving with the help of the computation block

1014593 6

following equation systems: in the initial 'stage of the submission

(7)

_C1 - "-az in the next stage of final grinding

• x ’

'39.1 ~ ^ C2 £ 2 ^β ^ ² 99 · 2 ^_ ^ C2 * -χ)?

where e is the base of the natural logarithm.

The current time is C, and is measured in the time interval measurement unit 19, whose operation is synchronized by the signals of the first differentiating device 17 (time reference C,) and the first zero-body 4 (time reference C ₂ ). Information about the current values of time C, and C _{g is} fed to the fifth input of the computation unit 18, which performs computational operations according to equations (7) and (8). The lateral feed rate of the caliper 21 is determined by differentiating the 5 _s signal (s) with the second differentiating device 23. Information about the values of ° τιθ of the velocities Y _{C (} and U _C2) goes to the fourth input of the calculating unit 18.

The values of the time constant T _о ^ determined at the first and second stages of processing and numerically equal, respectively, T _о ^ = С, and = Ц, are remembered by memory block 24, from where they arrive as a correction signal at the outputs of zero-organs 4 and 5. Principles of automatic correction processing mode, depending on the measured value of the time constant T _о ^ are visible from FIG. 2. With a sharp cutting circle, the metal removal rate as a current allowance, U _m (8), flows in accordance with curve 25-31-32-33-34-0. In this case, the switching speed of the cross feed is carried out at the values of the allowance of 5, and 5 ₂ .

The circle blunt entails an increase in the time constant and the ν _Μ (5) trajectory goes with a blunt circle along the curve 25-35-43-44-34-0. Zero-organs 4 and 5 trigger in this case with the values of the current allowance 5 ₃ and 84 respectively. The removal rate of allowance V. at the time of completion of processing ¹

(8) ¹ °

15

20

35

40

45

50

55

(when the third null-organ 6 is triggered) practically does not depend on the circle blunting state, which guarantees the stabilization of the quality indicators of the machined parts with respect to the diametric size accuracy, roughness and absence of burns.

Claims (1)

Claims self-adjusting control system of the working cycle of the cross feed during mortise grinding, containing an allowance sensor, the outputs of which are connected through the first converter to the first, second and third numerical bodies, a memory unit, a finishing allowance setting device, the output of which is connected to the first zero-body, setpoint device nursing allowance, the output of which is connected with the second null-organ, connected through the corresponding actuators with the drive mechanism of the cross feed to the speed setter is rough feed, speed feed final adjuster and speed caliper fast retractor speed controller, which differs with the fact that, in order to improve the accuracy and performance, as well as to stabilize the quality indicators of machining parts, the sensor for measuring the grinding wheel stroke associated with the second transducer is added to the system connected to the output of the first inverter first differentiating device connected to the output of the second inverter second differentiating device connected to the outputs of the first the second transducer is a subtractor, a computing unit whose output through the memory block is connected to the inputs of the first and second zero-bodies, and the inputs are connected to the outputs of the first differentiating device, the second differentiating device, the subtractive device, the first zero-organ and the output to ka measure time intervals, while the inputs of the unit measuring the time intervals associated with the findings of the first differentiating device and the first null-organ, the executive elements of the rough feed, chi tovoy feeding and rapid retraction respectively connected from the output of the first, second and third zero - organs. 1414593 g